From 6e34dcea479d835dc2493af56800d4a0f214885c Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 02:19:59 +0400
Subject: [PATCH 01/10] Migrate plugin Gradle to built-in Kotlin

---
 android/build.gradle | 29 +++++++++++------------------
 1 file changed, 11 insertions(+), 18 deletions(-)

diff --git a/android/build.gradle b/android/build.gradle
index 701bcac..806c90f 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -1,19 +1,6 @@
 group = "dev.fluttercommunity.android_id"
 version = "1.0-SNAPSHOT"
 
-buildscript {
-    ext.kotlin_version = "2.1.0"
-    repositories {
-        google()
-        mavenCentral()
-    }
-
-    dependencies {
-        classpath("com.android.tools.build:gradle:8.7.2")
-        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version")
-    }
-}
-
 allprojects {
     repositories {
         google()
@@ -22,7 +9,11 @@ allprojects {
 }
 
 apply plugin: "com.android.library"
-apply plugin: "kotlin-android"
+
+def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize(".")[0] as int
+if (agpMajor < 9) {
+    apply plugin: "kotlin-android"
+}
 
 android {
     if (project.android.hasProperty("namespace")) {
@@ -36,10 +27,6 @@ android {
         targetCompatibility = JavaVersion.VERSION_17
     }
 
-    kotlinOptions {
-        jvmTarget = "17"
-    }
-
     sourceSets {
         main.java.srcDirs += "src/main/kotlin"
         test.java.srcDirs += "src/test/kotlin"
@@ -66,3 +53,9 @@ android {
         }
     }
 }
+
+kotlin {
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
+    }
+}

From e38e4c0d4bddbbab90bd85751a447c56d49f7633 Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 02:21:13 +0400
Subject: [PATCH 02/10] Migrate example app to built-in Kotlin

---
 example/android/app/build.gradle                    | 13 +++++++------
 .../gradle/wrapper/gradle-wrapper.properties        |  2 +-
 example/android/settings.gradle                     |  3 +--
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/example/android/app/build.gradle b/example/android/app/build.gradle
index 3ab4a50..5bed1cb 100644
--- a/example/android/app/build.gradle
+++ b/example/android/app/build.gradle
@@ -1,7 +1,6 @@
 plugins {
     id "com.android.application"
-    id "kotlin-android"
-    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
+    // The Flutter Gradle Plugin must be applied after the Android Gradle plugin.
     id "dev.flutter.flutter-gradle-plugin"
 }
 
@@ -33,10 +32,6 @@ android {
         targetCompatibility = JavaVersion.VERSION_17
     }
 
-    kotlinOptions {
-        jvmTarget = "17"
-    }
-
     defaultConfig {
         // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
         applicationId = "dev.fluttercommunity.android_id_example"
@@ -60,3 +55,9 @@ android {
 flutter {
     source = "../.."
 }
+
+kotlin {
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
+    }
+}
diff --git a/example/android/gradle/wrapper/gradle-wrapper.properties b/example/android/gradle/wrapper/gradle-wrapper.properties
index 6b74f0f..bdc0141 100644
--- a/example/android/gradle/wrapper/gradle-wrapper.properties
+++ b/example/android/gradle/wrapper/gradle-wrapper.properties
@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.10.2-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.3.1-bin.zip
diff --git a/example/android/settings.gradle b/example/android/settings.gradle
index 72e8d42..6464403 100644
--- a/example/android/settings.gradle
+++ b/example/android/settings.gradle
@@ -18,8 +18,7 @@ pluginManagement {
 
 plugins {
     id "dev.flutter.flutter-plugin-loader" version "1.0.0"
-    id "com.android.application" version "8.7.2" apply false
-    id "org.jetbrains.kotlin.android" version "2.1.0" apply false
+    id "com.android.application" version "9.1.1" apply false
 }
 
 include ":app"

From 8bdc1b9f7ab59b887f6867064f797a9cdbc3c482 Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 02:21:49 +0400
Subject: [PATCH 03/10] Bump built-in Kotlin release to 0.5.2

---
 CHANGELOG.md         | 13 +++++++++++++
 example/pubspec.lock |  2 +-
 pubspec.yaml         |  2 +-
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index a712696..5d930ad 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,16 @@
+## 0.5.2
+
+* Support Android Gradle Plugin 9 and Flutter's built-in Kotlin mode while keeping
+  AGP 8 and Flutter's temporary `android.builtInKotlin=false` opt-out working.
+* Stop declaring plugin-owned Android Gradle Plugin and Kotlin Gradle Plugin classpaths.
+* Update the example Android app to Android Gradle Plugin 9.1.1.
+* Tested the example integration test with Flutter 3.44.0 and 3.44.4 on AGP 9
+  opt-out mode, and Flutter 3.32.8, 3.35.7, and 3.41.9 on AGP 8 legacy mode.
+* Verified AGP 9 built-in Kotlin mode with a release build; Flutter's current
+  `integration_test` Android package still blocks a full opt-in integration test.
+* Thanks to @raph5640, @kururu-abdo, @Joschiller, and @iamnfinity for reporting
+  the AGP 9 build problem.
+
 ## 0.5.1
 
 * Add integration tests to verify plugin functionality across Android API levels
diff --git a/example/pubspec.lock b/example/pubspec.lock
index b750e42..34a9956 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -7,7 +7,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "0.5.1"
+    version: "0.5.2"
   async:
     dependency: transitive
     description:
diff --git a/pubspec.yaml b/pubspec.yaml
index 0fb9dc2..a49f986 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -13,7 +13,7 @@ topics:
   - android
   - native
 
-version: 0.5.1
+version: 0.5.2
 
 environment:
   sdk: '>=3.0.0 <4.0.0'

From bf2c3e15a34677c96c35a263547cf878cf631560 Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 02:27:29 +0400
Subject: [PATCH 04/10] Opt example out of AGP new DSL

---
 example/android/gradle.properties | 1 +
 1 file changed, 1 insertion(+)

diff --git a/example/android/gradle.properties b/example/android/gradle.properties
index 3b5b324..b942162 100644
--- a/example/android/gradle.properties
+++ b/example/android/gradle.properties
@@ -1,3 +1,4 @@
 org.gradle.jvmargs=-Xmx4G -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
 android.enableJetifier=true
+android.newDsl=false

From f91b1c8e26eeb87e14d933e28b5c30a3e55f2de0 Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 02:44:07 +0400
Subject: [PATCH 05/10] Document AGP 9 compatibility guidance

---
 README.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/README.md b/README.md
index 842b8f1..7260e2c 100644
--- a/README.md
+++ b/README.md
@@ -40,6 +40,23 @@ try {
 
 **Note:** `getId()` returns `null` on non-Android platforms (iOS, Web, etc.). On Android, it throws `MissingPluginException` if the plugin is not properly registered (see more [below](https://pub.dev/packages/android_id#troubleshooting)).
 
+## Android build compatibility
+
+`android_id` supports Android Gradle Plugin 9 and Flutter's built-in Kotlin mode.
+It also keeps working with AGP 8 and Flutter's temporary
+`android.builtInKotlin=false` opt-out.
+
+The plugin no longer provides its own Android Gradle Plugin or Kotlin Gradle
+Plugin classpaths. It only applies the Kotlin Gradle Plugin when the host build
+still needs it. This fixes errors such as:
+
+```text
+The 'org.jetbrains.kotlin.android' plugin is no longer required for Kotlin
+support since AGP 9.0.
+```
+
+Most Flutter apps should not need app-code changes.
+
 ## Important
 
 Please note that on `Android 8` and above, the `Android ID` is not unique per device, but also per signing key the app was built with:

From 6175e73e797f69a63197b3d32f73abcccf4503ca Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 04:11:29 +0400
Subject: [PATCH 06/10] Pub get with Flutter 3.44.4

---
 example/pubspec.lock | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/example/pubspec.lock b/example/pubspec.lock
index 34a9956..fcd208e 100644
--- a/example/pubspec.lock
+++ b/example/pubspec.lock
@@ -28,10 +28,10 @@ packages:
     dependency: transitive
     description:
       name: characters
-      sha256: f71061c654a3380576a52b451dd5532377954cf9dbd272a78fc8479606670803
+      sha256: faf38497bda5ead2a8c7615f4f7939df04333478bf32e4173fcb06d428b5716b
       url: "https://pub.dev"
     source: hosted
-    version: "1.4.0"
+    version: "1.4.1"
   clock:
     dependency: transitive
     description:
@@ -133,26 +133,26 @@ packages:
     dependency: transitive
     description:
       name: matcher
-      sha256: dc58c723c3c24bf8d3e2d3ad3f2f9d7bd9cf43ec6feaa64181775e60190153f2
+      sha256: dc0b7dc7651697ea4ff3e69ef44b0407ea32c487a39fff6a4004fa585e901861
       url: "https://pub.dev"
     source: hosted
-    version: "0.12.17"
+    version: "0.12.19"
   material_color_utilities:
     dependency: transitive
     description:
       name: material_color_utilities
-      sha256: f7142bb1154231d7ea5f96bc7bde4bda2a0945d2806bb11670e30b850d56bdec
+      sha256: "9c337007e82b1889149c82ed242ed1cb24a66044e30979c44912381e9be4c48b"
       url: "https://pub.dev"
     source: hosted
-    version: "0.11.1"
+    version: "0.13.0"
   meta:
     dependency: transitive
     description:
       name: meta
-      sha256: e3641ec5d63ebf0d9b41bd43201a66e3fc79a65db5f61fc181f04cd27aab950c
+      sha256: "1741988757a65eb6b36abe716829688cf01910bbf91c34354ff7ec1c3de2b349"
       url: "https://pub.dev"
     source: hosted
-    version: "1.16.0"
+    version: "1.18.0"
   path:
     dependency: transitive
     description:
@@ -234,10 +234,10 @@ packages:
     dependency: transitive
     description:
       name: test_api
-      sha256: "522f00f556e73044315fa4585ec3270f1808a4b186c936e612cab0b565ff1e00"
+      sha256: "949a932224383300f01be9221c39180316445ecb8e7547f70a41a35bf421fb9e"
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.6"
+    version: "0.7.11"
   vector_math:
     dependency: transitive
     description:
@@ -263,5 +263,5 @@ packages:
     source: hosted
     version: "3.1.0"
 sdks:
-  dart: ">=3.8.0 <4.0.0"
+  dart: ">=3.10.0-0 <4.0.0"
   flutter: ">=3.18.0-18.0.pre.54"

From c0dbc9d580b839d205fc703d55fa0151b075f7dd Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 04:28:48 +0400
Subject: [PATCH 07/10] Support built-in Kotlin opt-out

---
 android/build.gradle | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/android/build.gradle b/android/build.gradle
index 806c90f..1cdb33c 100644
--- a/android/build.gradle
+++ b/android/build.gradle
@@ -10,9 +10,17 @@ allprojects {
 
 apply plugin: "com.android.library"
 
-def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize(".")[0] as int
-if (agpMajor < 9) {
-    apply plugin: "kotlin-android"
+def agpMajor = com.android.Version.ANDROID_GRADLE_PLUGIN_VERSION.tokenize('.')[0] as int
+boolean hasBuiltInKotlinSupport = agpMajor >= 9
+
+def builtInKotlinProperty = findProperty('android.builtInKotlin')
+boolean isBuiltInKotlinEnabled = builtInKotlinProperty == null ||
+        builtInKotlinProperty.toString().toBoolean()
+
+boolean shouldApplyKotlinGradlePlugin = !hasBuiltInKotlinSupport || !isBuiltInKotlinEnabled
+
+if (shouldApplyKotlinGradlePlugin) {
+    apply plugin: 'kotlin-android'
 }
 
 android {

From f2ad22cad4c99fba05f5b7bb3932f58f958aa7d0 Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 06:47:43 +0400
Subject: [PATCH 08/10] Remove example AGP new DSL opt-out

---
 example/android/gradle.properties | 1 -
 1 file changed, 1 deletion(-)

diff --git a/example/android/gradle.properties b/example/android/gradle.properties
index b942162..3b5b324 100644
--- a/example/android/gradle.properties
+++ b/example/android/gradle.properties
@@ -1,4 +1,3 @@
 org.gradle.jvmargs=-Xmx4G -XX:+HeapDumpOnOutOfMemoryError
 android.useAndroidX=true
 android.enableJetifier=true
-android.newDsl=false

From cb41cdb5f2056fbb9f5a1b7fdca676c6f0baa438 Mon Sep 17 00:00:00 2001
From: Joachim Tobias Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 06:52:24 +0400
Subject: [PATCH 09/10] Clarify changelog test matrix

---
 CHANGELOG.md | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5d930ad..58797b0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,10 +4,16 @@
   AGP 8 and Flutter's temporary `android.builtInKotlin=false` opt-out working.
 * Stop declaring plugin-owned Android Gradle Plugin and Kotlin Gradle Plugin classpaths.
 * Update the example Android app to Android Gradle Plugin 9.1.1.
-* Tested the example integration test with Flutter 3.44.0 and 3.44.4 on AGP 9
-  opt-out mode, and Flutter 3.32.8, 3.35.7, and 3.41.9 on AGP 8 legacy mode.
-* Verified AGP 9 built-in Kotlin mode with a release build; Flutter's current
-  `integration_test` Android package still blocks a full opt-in integration test.
+* Tested example integration tests with:
+
+  | Flutter | AGP | Kotlin mode |
+  | --- | --- | --- |
+  | 3.44.4 stable | 9.1.1 | Flutter AGP 9 opt-out |
+  | 3.44.0 | 9.1.1 | Flutter AGP 9 opt-out |
+  | 3.41.9 | 8.13.2 | legacy KGP |
+  | 3.35.7 | 8.13.2 | legacy KGP |
+  | 3.32.8 | 8.13.2 | legacy KGP |
+
 * Thanks to @raph5640, @kururu-abdo, @Joschiller, and @iamnfinity for reporting
   the AGP 9 build problem.
 

From 945e2aa8f664f94344907a6c657c499af21c26f4 Mon Sep 17 00:00:00 2001
From: Joachim Nohl <43643339+nohli@users.noreply.github.com>
Date: Fri, 3 Jul 2026 09:23:20 +0400
Subject: [PATCH 10/10] Use correct GitHub handle

---
 CHANGELOG.md | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 58797b0..c05c793 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,8 +14,7 @@
   | 3.35.7 | 8.13.2 | legacy KGP |
   | 3.32.8 | 8.13.2 | legacy KGP |
 
-* Thanks to @raph5640, @kururu-abdo, @Joschiller, and @iamnfinity for reporting
-  the AGP 9 build problem.
+* Thanks to @raph5640, @amanvishwakarma96, and @Joschiller for reporting the AGP 9 build problem.
 
 ## 0.5.1